This paper estimates the impact of incumbency on campaign contributions based on data for the U.S. House of Representatives during the period 1980 - 2006. The paper exploits that many candidates - both winning and losing - run for office more than once and uses a regression discontinuity design to estimate the causal effect of incumbency on campaign contributions. The results indicate that on average incumbency leads to a 50% jump in campaign receipts. However, there is considerable heterogeneity in the treatment effect. First, consistent with Snyder (1990), the financial incumbency advantage is greater for the subgroup of "investor-contributors" (e.g. PACs associated with corporations and unions) compared to "consumer-contributors" (individuals and non-connected PACs). Second, the financial incumbency advantage has been growing over time: on average the jump in campaign contributions caused by incumbency has grown approximately 9% per election. Third, the jump in campaign receipts caused by incumbency seems primarily to be driven by Republican incumbents.